Error detection

ABSTRACT

A method for detecting a writing error of a datum in memory includes: storing at least two parts of equal size of a binary word representative of said datum at the same address in at least two identical memory circuits, and comparing internal control signals of the two memory circuits to determine existence of the writing error.

PRIORITY CLAIM

This application claims the priority benefit of French Application forPatent No. 1909725, filed on Sep. 4, 2019, the content of which ishereby incorporated by reference in its entirety to the maximum extentallowable by law.

TECHNICAL FIELD

The present disclosure relates generally to electronic systems andcircuits and, more specifically, to electronic systems and circuitscomprising a memory. The present disclosure still more specificallyrelates to the reading and writing of data in these memories and, morespecifically, to the detection of errors during the reading and writingof data.

BACKGROUND

Data management, during the operation of a system, or an electroniccircuit, generally requires the use of one or several memories.Operating data are, for example, written and/or read from these memoriesbefore, or after, having been used.

Many errors, or faults, can be encountered during the reading and/orwriting of a datum in a memory. As an example, a reading error mayconsist of the reading of a datum at an incorrect address. A writingerror may consist of writing a datum at an incorrect address. Theseerrors can be accidental or deliberate. As an example, a deliberateerror may be produced by a fault injection method, for exampleimplemented by an attacker, with the aim of altering the operation of anelectronic system.

It would be desirable to be able to improve, at least partially, certainaspects of methods for reading and/or writing data in memory and, morespecifically, improve certain aspects of methods for detecting errors inreading and/or writing data in memory.

There is a need for more reliable methods for reading and/or writingdata in memory.

There is a need for better performing methods for detecting errors inreading and/or writing data in memory.

There is a need for methods for detecting errors in reading and/orwriting that are configured to detect errors in which data are writtenat an incorrect address.

SUMMARY

One embodiment addresses all or some of the drawbacks of the knownmethods for writing data in memory.

One embodiment addresses all or some of the drawbacks of the knownmethods for reading data in memory.

One embodiment addresses all or some of the drawbacks of the knownmethods for detecting errors in reading and/or writing in memory.

One embodiment provides a method for detecting a writing error of adatum in memory in which: at least two parts of equal size of a binaryword representative of said datum are stored at the same address in atleast two identical memory circuits; and internal control signals of thetwo memory circuits are compared.

According to one embodiment, the internal signals comprise a wordsignal.

According to one embodiment, the internal signals comprise a selectionsignal of one of the memory circuits.

According to one embodiment, the internal signals comprise a writingactivation signal.

According to one embodiment, the internal signals comprise aselection/column number signal.

According to one embodiment, the internal signals comprise aselection/row number signal.

According to one embodiment, the binary word is obtained from said datumand an error correcting or detecting code, said error correcting ordetecting code being representative of said datum and said address.

According to one embodiment, the binary word is obtained byconcatenation of said datum and the error correcting or detecting code.

According to one embodiment, the error correcting or detecting code isrepresentative of said datum and said address.

According to one embodiment, the correcting or error detecting code isobtained by a signature method.

Another embodiment provides a method for writing a datum in memory, inwhich: a binary word, representative of said datum and an errorcorrecting or detecting code, is split into at least a first part and asecond part; and said first part is written at a logical address in afirst memory circuit; and said second part is written at said logicaladdress in a second memory circuit configured to store as many binarywords as said first memory circuit, said error correcting or detectingcode being dependent on said datum and said address.

According to one embodiment, said first and second parts are of equalsize.

According to one embodiment, the binary word is a concatenation of saiddatum and said correcting or error detecting code.

According to one embodiment, said datum and said address are supplied bya single first processor.

According to one embodiment, said datum and said address are supplied byat least one second processor and a third processor.

According to one embodiment, said datum supplied by the second processoris compared to said datum supplied by the third processor, and saidaddress supplied by the second processor is compared to said addresssupplied by the third processor.

According to one embodiment, the second processor supplies said addressto one of said at least two memory circuits, and the third processorsupplies said address to another of said at least two memory circuits.

According to one embodiment, the second processor supplies said addressto said at least two memory circuits.

According to one embodiment, said first and second memory circuits arethe same size.

According to one embodiment, internal control signals of said at leasttwo memory circuits are compared.

Another embodiment provides a method for reading a datum writtenaccording to the method disclosed above.

According to one embodiment, said binary word is formed by concatenatingsaid first and second parts read in said first and second memorycircuits.

According to one embodiment, the datum is obtained by removing thecorrecting or error detecting code from the binary word.

Another embodiment provides a method for detecting an error in a datumwritten by the method disclosed above, wherein the error correcting ordetecting code is computed again from the datum read by the methoddisclosed above.

According to one embodiment, the correcting or error detecting code isverified.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features and advantages, as well as others, will bedescribed in detail in the following description of specific embodimentsgiven by way of illustration and not limitation with reference to theaccompanying drawings, in which:

FIG. 1 shows, schematically and in block diagram form, part of anarchitecture of one embodiment of an electronic system;

FIG. 2 shows, schematically and in block diagram form, another part ofthe architecture of the system of FIG. 1;

FIG. 3 shows, schematically and in block diagram form, part of anarchitecture of one embodiment of an electronic system;

FIG. 4 shows, schematically and in block diagram form, another part ofthe architecture of the system of FIG. 3;

FIG. 5 shows, schematically and in block diagram form, part of anarchitecture of one embodiment of an electronic system;

FIG. 6 shows, schematically and in block diagram form, another part ofthe architecture of the system of FIG. 5;

FIG. 7 shows, schematically and in block diagram form, part of anarchitecture of another embodiment of an electronic system;

FIG. 8 shows, schematically and in block diagram form, another part ofthe architecture of the system of FIG. 7;

FIG. 9 shows, schematically and in block diagram form, part of anarchitecture of a memory circuit; and

FIG. 10 shows, schematically and in block diagram form, part of thearchitecture of another embodiment of an electronic system.

DETAILED DESCRIPTION

Like features have been designated by like references in the variousfigures. In particular, the structural and/or functional features thatare common among the various embodiments may have the same referencesand may dispose identical structural, dimensional and materialproperties.

For the sake of clarity, only the operations and elements that areuseful for an understanding of the embodiments described herein havebeen illustrated and described in detail.

Unless indicated otherwise, when reference is made to two elementsconnected together, this signifies a direct connection without anyintermediate elements other than conductors, and when reference is madeto two elements coupled together, this signifies that these two elementscan be connected or they can be coupled via one or more other elements.

In the following disclosure, unless indicated otherwise, when referenceis made to absolute positional qualifiers, such as the terms “front”,“back”, “top”, “bottom”, “left”, “right”, etc., or to relativepositional qualifiers, such as the terms “above”, “below”, “higher”,“lower”, etc., or to qualifiers of orientation, such as “horizontal”,“vertical”, etc., reference is made to the orientation shown in thefigures.

Unless specified otherwise, the expressions “around”, “approximately”,“substantially” and “in the order of” signify within 10%, and preferablywithin 5%.

In the remainder of the disclosure, splitting, cutting or division of aninitial binary word into several parts will refer to the formation ofseveral secondary binary words from bits of the initial binary word.More specifically, each secondary binary word is made up such that theconcatenation of all of the secondary binary words, in a specific order,yields the initial binary word.

Additionally, in the remainder of the description, a logical addressrefers to an address generated by a processor and intended for a memorycircuit. This address is decoded by an address decoding circuitassociated with the memory circuit and that supplies a physical circuitin terms of coordinates (row-column) in the memory plane.

FIG. 1 shows, schematically and in block diagram form, part 10 of anarchitecture of one embodiment of an electronic system 1. The part 10 isconfigured to write data in memory of the electronic circuit 1.

The part 10 comprises: a processor 101 (CPU); a circuit 102 (EDC GEN)for generating an error correcting or detecting code; a circuit 103 (EDCADD) for forming a binary word; a circuit 104 (SPLIT) for dividing abinary word; two memory circuits 105 (MEM1) and 106 (MEM2); and anaddress decoding circuit 107 (ADD DEC).

The processor 101 is a processor configured to request the writing ofdata in the memories 105 and 106. The processor 101 supplies, as output,a datum Data1 to be written and a logical address AddL1. The addressAddL1 is the logical address at which the datum Data1 must be written inmemory. As an example, the logical address AddL1 is a binary word whosebits of high weight indicate the row of the memory circuit in which thebinary word must be written, and the bits of low weight indicate thecolumn of the memory circuit in which the binary word must be written.

The circuit 102 for generating an error correcting or detecting code isa circuit configured to compute an error detecting code (EDC) EDC1, oran error correcting code (ECC), representative of the datum Data1 andthe logical address AddL1. Thus, the circuit 102 receives, as input, thedatum Data1 and the logical address AddL1, and supplies, as output, theerror correcting or detecting code EDC1. As an example, the errordetecting code EDC1 is obtained by using a signature algorithm.

The circuit 103 for forming a binary word is a circuit configured toform a binary word Code1 representative of the datum Data1 and the codeEDC1. The circuit 103 receives, as input, the datum Data1 and the codeEDC1, and supplies, as output, the binary word Code1. As an example, thedatum Data1 and the code EDC1 are concatenated by the circuit 103 inorder to form the binary word Code1. The order in which the datum Data1and the code EDC1 are concatenated in order to form the binary wordCode1 is unimportant.

The binary word division circuit 104 is a circuit configured to splitthe binary word Code1 into several binary words. The circuit 104receives the binary word Code1 as input and, in this example, suppliestwo binary words Code1A and Code1B as output. In other words, theconcatenation of the binary words Code1A and Code1B, in a specificorder, yields the binary word Code1. The binary words Code1A and Code1B,for example, have different sizes. As a variant, the binary words Code1Aand Code1B are the same size, that is to say, they each comprise half ofthe bits of the binary word Code1.

The address decoding circuit 107 is a circuit configured to supplyphysical addresses readable by memory circuits from a logical address.The circuit 107 receives the logical address AddL1 as input, andsupplies two physical addresses Add1A and Add1B as output. The circuit107 more specifically makes it possible to define, from the logicaladdress AddL1 supplied by the processor 101, the two physical addressesAdd1A and Add1B at which the binary words Code1A and Code1B will bewritten in the memory circuits 105 and 106. As an example, the addressesAdd1A and Add1B are identical.

The memory circuits 105 and 106 are configured to store the binary wordsCode1A and Code1B respectively at the addresses Add1A and Add1B. Thus,the memory 105 receives the binary word Code1A and the address Add1A asinput, and the memory 106 receives the binary word Code1B and theaddress Add1B as input. The memory circuits 105 and 106 are configuredto store the same number of binary words. The memory circuits 105 and106 are, for example, volatile memories. As an example, the memorycircuits 105 and 106 are the same size.

As a variant, the part 10 could comprise more than two memory circuitswith an identical structure and size. In this case, the circuit 104would be configured to supply as many binary words as there are memorycircuits comprised in the part 10. In other words, the circuit 104 isconfigured to divide the binary word Code1 into as many parts as thereare memory circuits comprised in the part 10. Additionally, the circuit107 is configured to supply as many physical addresses from the logicaladdress AddL1 as there are memory circuits comprised in the part 10.

A method for writing the datum Data1 implementing the part 10 of thesystem 1 in memory is as follows. When the processor 101 wishes to storethe datum Data1 in memory, it generates the address AddL1 at which itwishes to store the datum. The processor 101 then supplies the datumData1 and the logical address AddL1 to the circuit 102 for which thelatter generates the code EDC1. In parallel, the address AddL1 isconverted into two physical addresses Add1A and Add1B by the circuit107. The datum Data1 and the code EDC1 are next used, by the circuit103, to supply the binary word Code1. The binary word Code1 is thendivided into two parts, the two binary words Code1A and Code1B by thecircuit 104. The binary words Code1A and Code1B are stored,respectively, in the memory circuit 105 and in the memory circuit 106 atthe addresses Add1A and Add1B. Thus, the datum Data1 is stored in thememory circuits 105 and 106, in the form of binary words Code1A andCode1B.

FIG. 2 shows, schematically and in block diagram form, another part 11of the architecture of the embodiment of the electronic system 1, thepart 10 of which is described in relation with FIG. 1. The part 11 isconfigured for writing data in memories of the electronic system 1. Morespecifically, in FIG. 2, the part 11 is configured to read the datumData1 written at the address AddL1 as described in relation with FIG. 1.

The part 11 comprises: a processor 111 (CPU); a circuit 112 (EDC CHECK)for checking an error correcting or detecting code; a circuit 113 (EDCREMOVAL) for recovering a datum; a circuit 114 (MERGE) for concatenatingbinary words; the two identical memory circuits 105 (MEM1) and 106(MEM2); and the address decoding circuit 107 (ADD DEC).

The processor 111 is a processor configured to request the reading ofdata in the memories 105 and 106. The processor 111 supplies an address,for example the logical address AddL1 described in relation with FIG. 1,as output, and receives a datum corresponding to the address, that is tosay, the datum Data1 described in relation with FIG. 1, as input. Theprocessor 111 is, for example, the same processor as the processor 101described in relation with FIG. 1, but as a variant, the processor 111can be a separate processor from the processor 101 described in relationwith FIG. 1.

The circuit 112 for checking an error correcting or detecting code is acircuit configured to check the code EDC1 associated with the datumData1. The circuit 112 receives the binary word Code1 and the logicaladdress AddL1 as input, and supplies an error signal ErrEDC1 as output.To check the code EDC1, the circuit 112 finds, from the binary wordCode1, the datum Data1 and the code EDC1. Next, the circuit 112 computesa new error detecting or correcting code from the datum Data1 and theaddress AddL1 supplied by the processor 111. The new code is thencompared to the code EDC1. If they are the same, then there is no error.If they are not, then there is an error. Any error is indicated by meansof the signal ErrEDC1. The circuit 102 disclosed in relation with FIG. 1is, for example, part of the circuit 112, but as a variant, the circuits102 and 112 can be separate circuits.

The data recovery circuit 113 is a circuit configured to recover thedatum Data1 from the binary word Code1. The circuit 113 receives thebinary word Code1 as input, and supplies the datum Data1 as output. Asan example, when the binary word Code1 is a concatenation of the datumData1 and the code EDC1, the circuit 113 is configured to truncate thecode EDC1 of the binary word Code1, and thus to keep only the datumData1. The circuit 113 and the circuit 103 described in relation withFIG. 1 can, for example, be part of a same circuit, or as a variant canbe two separate circuits.

The binary word concatenation circuit 114 is a circuit configured tofind the binary word Code1 from two binary words Code1A and Code1B.Thus, the circuit 114 receives the binary words Code1A and Code1B asinput, and supplies the binary word Code1 as output. The circuit 114 isparticularly configured to concatenate the binary words Code1A andCode1B in the correct order in order to find the initial binary wordCode1. The circuit 114 and the circuit 104 described in relation withFIG. 1 can, for example, be part of a same circuit, or as a variant canbe two separate circuits.

As a variant, the parts 10 and 11 could comprise more than two memorycircuits. In this case, the circuit 114 is configured to receive as manybinary words as there are memory circuits comprised in the parts 10 and11 as input. In other words, the circuit 114 is configured to receivethe binary word Code1 from as many binary words as there are memorycircuits comprised in the parts 10 and 11. Additionally, in this case,the circuit 107 is configured to supply as many physical addresses asnecessary.

A method for reading the datum Data1 implementing the part 11 of thesystem 1 in memory is as follows. The processor 111 supplies the circuit107 with the address AddL1 at which it wishes to read a datum, in thecase at hand the datum Data1. The circuit 107 supplies the memories 105and 106 with the physical addresses Add1A and Add1B coming from thelogical address AddL1. The binary word Code 1A is stored at the addressAdd1A of the memory circuit 105, and the binary word Code1B is stored atthe address Add1B of the memory circuit 106. The memory circuits 105 and106 supply the circuit 114 with the two binary words Code1A and Code1Bto reform the binary word Code1. The circuit 113 is tasked withextracting the datum Data1 from the binary word Code1 and sending it tothe processor 111. The circuit 112 in turn checks that there is noerror, by checking the code EDC1.

One advantage of this embodiment is that, during the reading method, thecircuit 112 makes it possible to detect an addressing error of the datumData 1. Indeed, the code EDC1 being representative of the datum Data1and the logical address AddL1 at which the datum was written, thecomparison of the code EDC1 to a code generated from the logical addressAddL1 supplied by the processor 111 can make it possible to detect adifference in logical addresses.

FIG. 3 shows, schematically and in block diagram form, part 20 of anarchitecture of one embodiment of an electronic system 2. The part 20 isconfigured to write data in memory of the electronic circuit 2.

The part 20 comprises: two processors 201 (CPU1) and 202 (CPU2); acircuit 203 (EDC Gen) for generating an error correcting or detectingcode; a circuit 204 (EDC ADD) for forming a binary word; a circuit 205(SPLIT) for dividing a binary word; two memory circuits 206 (MEM1) and207 (MEM2); two address decoding circuits 209A (ADD DEC 1) and 209B (ADDDEC 2); and a comparison circuit 208 (COMP).

The processors 201 and 202 are processors with identical structures andconfigured to supply the same data and controls. The processors 201 and202 are more specifically processors configured to request the writingof data in the memories 206 and 207. Each processor 201, 202 supplies adatum Data2 and a logical address AddL2 as output. The address AddL2 isthe logical address at which the datum Data2 must be written. Using twoprocessors 201 and 202 in parallel makes it possible, inter alia, todetect errors through redundancy checks.

The circuit 203 for generating an error correcting or detecting code isa circuit identical to the circuit 102 disclosed in relation withFIG. 1. The circuit 203 receives the datum Data2 coming from theprocessor 201, and the logical address AddL2 coming from the processor201, as input. The circuit 203 supplies an error correcting or detectingcode EDC2 as output.

The circuit 204 for forming a binary word is a circuit identical to thecircuit 103 disclosed in relation with FIG. 1. The circuit 204 receivesthe code EDC2 and the datum Data2 coming from the processor 201 asinput, and supplies a binary word Code2 as output.

The circuit 205 for dividing a binary word is a circuit identical to thecircuit 104 disclosed in relation with FIG. 1. The circuit 205 receivesthe binary word Code2 as input, and supplies two binary words Code2A andCode2B corresponding to two parts of the binary word Code2 as output.

The circuits 209A and 209B are circuits similar to the circuit 107disclosed in relation with FIG. 1. The circuit 209A receives the logicaladdress AddL2 coming from the processor 201, and supplies a physicaladdress Add2A as output. The circuit 209B receives the logical addressAddL2 coming from the processor 202, and supplies a physical addressAdd2B as output.

The memory circuits 206 and 207 are configured to store the binary wordsCode2A and Code2B respectively at the addresses Add2A and Add2B. Thememory circuits 206 and 207 are memory circuits configured to store thesame number of binary words. The memory circuit 206 receives the binaryword Code2A as input, as well as the address Ad2A coming from thecircuit 209A. The memory circuit 207 receives the binary word Code2B asinput, as well as the address Ad2B coming from the circuit 209B. Thememory circuits 206 and 207 are, for example, volatile memories. As anexample, the memory circuits 206 and 207 are the same size.

As a variant, the part 20 could comprise more than two memory circuitswith an identical structure and size. In this case, the circuit 205would be configured to supply as many binary words of the same size asthere are memory circuits comprised in the part 20. In other words, thecircuit 205 is configured to divide the binary word Code2 into as manybinary words as there are memory circuits comprised in the part 20.Additionally, the circuits 209A and 209B are configured, in this case,to supply as many physical addresses from the logical address AddL2 asthere are memory circuits comprised in the part 20.

The comparison circuit 208 is a circuit configured to compare the dataData2 supplied by the processors 201 and 202, and the logical addressesAddL2 supplied by the processors 201 and 202. If the data Data2transmitted by the two processors 201 and 202, or the addresses AddL2transmitted by the two processors 201 and 202, are not the same, then anerror is detected. The circuit 208 receives the data Data2 transmittedby the two processors 201 and 202 as input, as well as the addressesAddL2 transmitted by the two processors 201 and 202, and supplies anerror signal ErrComp20 as output. Any error detected by the circuit 208is transmitted via the error signal ErrComp20.

A method for writing the datum Data2 implementing the part 20 of thesystem 2 in memory is as follows. When the processors 201 and 202 wishto store the datum Data2 in memory, they generate the logical addressAddL2 at which they wish to store it. The processor 201 then suppliesthe datum Data2 and the logical address AddL2 to the circuit 203 forwhich the latter generates the code EDC2. In parallel, the logicaladdress AddL2 is converted into two physical addresses Add2A and Add2Brespectively by the circuits 209A and 209B. The code EDC2 is thereforerepresentative of the datum Data2 and the address AddL2 supplied by theprocessor 201. The datum Data2 and the code EDC2 are next used, by thecircuit 204, to supply the binary word Code2. The binary word Code2 isnext divided into the two binary words Code2A and Code2B, by the circuit205. The binary words Code2A and Code2B are stored, respectively, at theaddress Add2A in the memory circuit 206 and the address Add2B in thememory circuit 207.

FIG. 4 shows, schematically and in block diagram form, another part 21of the architecture of the embodiment of the electronic system 2, thepart 20 of which is described in relation with FIG. 3. The part 21 isconfigured for writing data in memories of the electronic system 2. Morespecifically, in FIG. 4, the part 21 is configured to read the datumData2 written at the logical address AddL2 as described in relation withFIG. 3.

The part 21 comprises: two processors 211 (CPU1) and 212 (CPU2); acircuit 213 (EDC CHECK) for checking an error correcting or detectingcode; a circuit 214 (EDC REMOVAL) for recovering a datum; a circuit 215(MERGE) for concatenating binary words; and the two identical memorycircuits 206 (MEM1) and 207 (MEM2); the two address decoding circuits209A (ADD DEC 1) and 209B (ADD DEC 2); and a comparison circuit 218(COMP).

The processors 211 and 212 are processors identical to the processor111. The processors 211 and 212 each supply, as output, the logicaladdress AddL2 at which they wish to read a datum, and each receive thedatum Data2. The processors 211 and 212 are, for example, the sameprocessors as the processors 201 and 202 described in relation with FIG.3, but as a variant, the processors 211 and 212 can be separateprocessors from the processors 201 and 202.

The circuit 213 for checking an error correcting or detecting code is acircuit identical to the circuit 112 disclosed in relation with FIG. 2.The circuit 213 receives the logical address AddL2 transmitted by theprocessor 211 and the binary word Code2 as input, and supplies an errorsignal ErrEDC2 as output. The circuit 213 and the circuit 203 describedin relation with FIG. 3 can, for example, be part of a same circuit, oras a variant can be two separate circuits.

The circuit 214 for recovering a datum is a circuit identical to thecircuit 113 disclosed in relation with FIG. 2. The circuit 214 receivesthe binary word Code2 as input, and supplies the datum Data2 as output.

The circuit 215 for concatenating binary words is a circuit identical tothe circuit 114 disclosed in relation with FIG. 2. The circuit 215receives the two binary words Code2A and Code2B as input, and suppliesthe binary word Code2 as output. The circuit 215 and the circuit 205described in relation with FIG. 3 can, for example, be part of a samecircuit, or as a variant can be separate circuits.

The circuits 209A and 209B convert the logical address AddL2respectively into the physical addresses Add2A and Add2B. The circuit209A receives the logical address AddL2 coming from the processor 211,and supplies the physical address Add2A as output. The circuit 209Breceives the logical address AddL2 coming from the processor 212, andsupplies the physical address Add2B as output.

The memory circuits 206 and 207 store the binary words Code2A and Code2Brespectively at the addresses Add2A and Add2B. The memory circuit 206receives the address Add2A from the circuit 209A, and the memory circuit207 receives the address Add2B from the circuit 209B.

As a variant, the parts 20 and 21 could comprise more than two memorycircuits. In this case, the circuit 215 is configured to receive as manybinary words as there are memory circuits comprised in the parts 20 and21 as input. In other words, the circuit 215 is configured to receivethe binary word Code2 from as many binary words as there are memorycircuits comprised in the parts 20 and 21. Additionally, the circuits209A and 209B are configured to supply as many physical addresses fromthe logical address AddL2 as there are memory circuits present in theparts 20 and 21.

The comparison circuit 218 is a circuit configured to compare thelogical addresses AddL2 transmitted by the processors 211 and 212. Thecomparison circuit 218 receives the address AddL2 supplied by theprocessor 211 and the address AddL2 supplied by the processor 212 asinput, and supplies an error signal ErrComp21 as output. If the logicaladdresses transmitted by the processors 211 and 212 are not identical,than an error is detected, and is transmitted by the error signalErrComp21. The circuit 218 and the circuit 208 described in relationwith FIG. 3 can, for example, be part of a same circuit, but, as avariant, the circuits 208 and 218 can be separate circuits.

A method for reading the datum Data2 implementing the part 21 of thesystem 2 in memory is as follows. The processors 211 and 212 supply thecircuits 209A and 209B with the address AddL2 at which they wish to reada datum, in the case at hand the datum Data2. The circuits 209A and 209Bsupply the physical addresses Add2A and Add2B to the memory circuits 206and 207. The comparison circuit 218 checks whether the processors 211and 212 are transmitting the same logical address AddL2. The binary wordCode2A is stored at the address Add2A of the memory circuit 206, and thebinary word Code2B is stored at the address Add2B of the memory circuit207. The memory circuits 206 and 207 supply the circuit 215 with the twobinary words Code2A and Code2B to reform the binary word Code2. Thecircuit 214 occupies itself finding the datum Data2 and transmitting itto the processors 211 and 212. The circuit 213 in turn checks that thereis no error.

One advantage of this embodiment is that, during the reading method, thecircuit 213 makes it possible to detect an addressing error of the datumData2. Indeed, the code EDC2 being representative of the datum Data2 andthe logical address at which the datum was written, the comparison ofthe code EDC2 to a code generated from the logical address AddL2supplied by the processor 211 can make it possible to detect adifference in logical addresses.

Another advantage of this embodiment is that using two processors 201and 202, and 211 and 212, in parallel makes it possible to detect theerrors emitted during the reading command or the writing command. Theseerrors are detected by the circuits 208 and 218.

FIG. 5 shows, schematically and in block diagram form, part 30 of anarchitecture of one embodiment of an electronic system 3. The part 30 isconfigured to write data in memory of the electronic circuit 3.

The electronic system 3 is similar to the electronic system 2, the parts20 and 21 of which are described in relation with FIGS. 3 and 4. Theelements shared by the systems 2 and 3 will not be described againhereinafter.

The part 30 comprises substantially the same circuits as the part 20 ofthe system 2. Thus, the part 30 comprises: two processors 201 (CPU1) and202 (CPU2); a circuit 203 (EDC Gen) for generating an error correctingor detecting code; a circuit 204 (EDC ADD) for forming a binary word; acircuit 205 (SPLIT) for dividing a binary word; two identical memorycircuits 206 (MEM1) and 207 (MEM2); an address decoding circuit 309 (ADDDEC); and a comparison circuit 208 (COMP).

The difference between the part 20 of the system 2 and the part 30 ofthe system 3 is that, in the part 30, the logical address AddL2 istransmitted by the processor 201 to the circuit 309, which is identicalto the circuit 107 described in relation with FIG. 1. The circuit 309supplies the two physical addresses Add2A and Add2B as output. The twomemory circuits 206 and 207 respectively receive the physical addressesAdd2A and Add2B from the circuit 309. In the part 20, each memorycircuit receives the physical address Add2A or Add2B from a differentdecoding circuit. In this embodiment, the processor 202 only suppliesthe logical address AddL2 to the comparison circuit 208.

FIG. 6 shows, schematically and in block diagram form, another part 31of the architecture of the embodiment of the electronic system 3, thepart 30 of which is described in relation with FIG. 5. The electronicsystem 3 is a preferred embodiment. The part 31 is configured forwriting data in memories of the electronic system 3. More specifically,in FIG. 6, the part 31 is configured to read the datum Data2 written atthe address AddL2 as described in relation with FIG. 3.

The electronic system 3 is similar to the electronic system 2, the parts20 and 21 of which are disclosed in relation with FIGS. 3 and 4. Theelements shared by the systems 2 and 3 will not be described againhereinafter.

The part 31 comprises some of the circuits of the part 21 of the system2. Thus, the part 31 comprises: two processors 211 (CPU1) and 212(CPU2); the circuit 213 (EDC CHECK) for checking an error correcting ordetecting code; the circuit 214 (EDC REMOVAL) for recovering a datum;the circuit 215 (MERGE) for concatenating binary words; and the twoidentical memory circuits 206 (MEM1) and 207 (MEM2); the addressdecoding circuit 309 (ADD DEC); and the comparison circuit 218 (COMP).

The difference between the part 21 of the system 2 and the part 31 ofthe system 3 is that, in the part 31, the two memory circuits 206 and207 receive the addresses Add2A and Add2B from the circuit 309. In thepart 20, each memory circuit receives the address Add2A or Add2B from adifferent address decoding circuit. In this embodiment, the processor212 only supplies the logical address AddL2 to the comparison circuit218.

One advantage of this embodiment is that, during the reading method, thecircuit 213 makes it possible to detect an addressing error of the datumData2. Indeed, the code EDC2 being representative of the datum Data2 andthe logical address at which the datum was written, the comparison ofthe code EDC2 to a code generated from the logical address AddL2supplied by the processor 211 makes it possible to detect a differencein logical addresses.

Another advantage of this embodiment is that the two binary words Code2Aand Code2B are written at physical addresses Add2A and Add2B, comingfrom the same logical address AddL2, in memory circuits 206 and 207,even if the logical addresses AddL2 transmitted by the processors 201and 202 are different in error.

FIG. 7 shows, schematically and in block diagram form, part 40 of anarchitecture of one embodiment of an electronic system 4. The part 40 isconfigured to write data in memory of the electronic circuit 4.

The part 40 comprises: two processors 401 (CPU1) and 402 (CPU2); twocircuits 403 (EDC GEN 1) and 404 (EDC GEN 2) for generating an errorcorrecting or detecting code; two circuits 405 (EDC ADD1) and 406 (EDCADD 2) for forming a binary word; circuits 407 (SPLIT 1) and 408 (SPLIT2) for dividing a binary word; two identical memory circuits 409 (MEM1)and 410 (MEM2); two address decoding circuits 412 (ADD DEC 1) and 413(ADD DEC2); and a comparison circuit 411 (COMP).

The processors 401 and 402 are similar to the processors 201 and 202 ofthe part 20 of the system 2 described in relation with FIG. 3. Theprocessors 401 and 402 have identical structures and configured tosupply the same data and controls. The processors 401 and 402 are morespecifically processors configured to request the writing of data in thememories 409 and 410. Each processor 401, 402 supplies a datum Data4 tobe written in memory and a logical address AddL4 as output. The addressAddL4 is the logical address at which the datum Data4 must be written inmemory. Using two processors 401 and 402 in parallel makes it possible,inter alia, to detect errors through redundancy checks.

The circuits 403 and 404 for generating an error correcting or detectingcode are circuits identical to the circuits 102 disclosed in relationwith FIG. 1. The circuit 403 receives the datum Data4 and the logicaladdress AddL4 both coming from the processor 401 as input, and suppliesa code EDC4 as output. The circuit 404 receives the datum Data4 and thelogical address AddL4 both coming from the processor 402 as input, andsupplies an error correcting or detecting code EDC4 as output.

The circuits 405 and 406 for forming a binary word are circuitsidentical to the circuit 103 disclosed in relation with FIG. 1. Thecircuit 405 receives the code EDC4 coming from the circuit 403 as input,and supplies the binary word Code4 as output. The circuit 406 receivesthe code EDC4 coming from the circuit 404 as input, and supplies thebinary word Code4 as output.

The circuits 407 and 408 for dividing a binary word are circuitsconfigured to divide the binary word Code4 into several binary words.The circuit 407 receives the binary word Code4 coming from the circuit405 as input, and in this example supplies the binary word Code4 and thebinary word Code2A as output. The circuit 408 receives the binary wordCode4 coming from the circuit 406 as input, and in this example suppliesthe binary word Code4 and the binary word Code2B as output.

The address decoding circuits 412 and 413 are circuits identical to thecircuit 107 disclosed in relation with FIG. 1. The circuits 412 and 413convert the logical address AddL4 respectively into the physicaladdresses Add4A and Add4B. The circuit 412 receives the logical addressAddL4 coming from the processor 401, and supplies the physical addressAdd4A as output. The circuit 413 receives the logical address AddL4coming from the processor 402, and supplies the physical address Add4Bas output.

The memory circuits 409 and 410 are memory circuits identical to thememory circuits 105 and 106 disclosed in relation with FIG. 1. Thememory circuit 409 receives the binary word Code4A coming from thecircuit 407 as input, as well as the address Add4A coming from thecircuit 412. The memory circuit 410 receives the binary word Code4Bcoming from the circuit 408 as input, as well as the address Add4Bcoming from the circuit 413. As an example, the memory circuits 409 and410 are the same size.

As a variant, the part 40 could comprise more than two memory circuits.In this case, the part 40 comprises as many circuits for generating anerror correcting or detecting code, as many circuits for forming abinary word, and as many circuits for dividing a binary word as thereare memory circuits in the part 40. Additionally, the binary worddividing circuits are configured to divide the binary word that theyreceive as input into a number of binary words equivalent to the numberof memory circuits comprised in the part 40. The address decodingcircuits 412 and 413 are configured to supply as many physical addressesas there are memory circuits comprised in the part 40.

The comparison circuit 411 is a circuit identical to the circuit 208disclosed in relation with FIG. 3. The circuit 411 receives the dataData4 transmitted by the processors 401 and 402 as input, as well as theaddresses AddL4 transmitted by the processors 401 and 402. The circuit411 supplies an error signal ErrComp40 as output.

A method for writing the datum Data4 implementing the part 40 of thesystem 4 in memory is as follows. When the processors 401 and 402 wishto store the datum Data4 in memory, they generate the logical addressAddL4 at which they wish to store it. The processor 401, respectively402, then supplies the datum Data4 and the logical address AddL4 to thecircuit 403, respectively 404, for which the latter generates the codeEDC4. In parallel, the processor 401, respectively 402, supplies theaddress AddL4 to the circuit 412, respectively 413, to obtain thephysical address Add4A, respectively Add4B. The code EDC4 is thereforerepresentative of the datum Data4 and the logical address AddL4 suppliedby the processors 401 and 402. The circuit 405 next generates the binaryword Code4 from the code EDC4 supplied by the circuit 403 and from thedatum Data4 supplied by the processor 401. The circuit 406 nextgenerates the binary word Code4 from the code EDC4 supplied by thecircuit 404 and from the datum Data4 supplied by the processor 402. Thecircuits 407 and 408 divide the binary words Code4, respectivelyreceived from the circuits 405 and 406, into the binary words Code4A andCode4B. The binary word Code4A is stored in the memory 409 at theaddress Add4A transmitted by the circuit 412, and the binary word Code4Bis stored in the memory 410 at the address Add4B transmitted by thecircuit 413.

FIG. 8 shows, schematically and in block diagram form, another part 42of the architecture of the embodiment of the electronic system 4, thepart 40 of which is described in relation with FIG. 7. The part 42 isconfigured for writing data in memories of the electronic system 4. Morespecifically, in FIG. 8, the part 42 is configured to read the datumData4 written at the logical address AddL4 in the memory circuits 409and 410 as described in relation with FIG. 7.

The part 42 comprises: two processors 421 (CPU1) and 422 (CPU2);circuits 423 (EDC CHECK 1) and 424 (EDC CHECK 2) for checking an errorcorrecting or detecting code; circuits 425 (EDC REMOVAL 1) and 426 (EDCREMOVAL 2) for recovering a datum; circuits 427 (MERGE 1) and 428 (MERGE2) for concatenating binary words; and the two memory circuits 409(MEM1) and 410 (MEM2); the two address decoding circuits 412 (ADD DEC 1)and 413 (ADD DEC 2); and a comparison circuit 431 (COMP).

The two processors 421 and 422 are processors identical to theprocessors 211 and 212 disclosed in relation with FIG. 4. The processors421 and 422 each supply, as output, the logical address AddL4 at whichthey wish to read a datum, and each receive the datum Data4. Theprocessors 421 and 422 are, for example, the same processors as theprocessors 401 and 402, but as a variant, the processors 421 and 422 canbe separate processors from the processors 401 and 402.

The circuits 423 and 424 for checking an error correcting or detectingcode are circuits identical to the circuit 112 disclosed in relationwith FIG. 2. The circuit 423 receives the logical address AddL4 comingfrom the processor 421 and the binary word Code4 coming from the circuit427 as input, and supplies an error signal ErrEDC42 as output. Thecircuit 424 receives the address AddL4 coming from the processor 422 andthe binary word Code4 coming from the circuit 428 as input, and suppliesan error signal ErrEDC42 as output. The circuits 403 and 423 can, forexample, be part of a same circuit, but, as a variant, can be separatecircuits. The circuits 404 and 424 can, for example, be part of a samecircuit, but, as a variant, can be separate circuits.

The circuits 425 and 426 for recovering a datum are circuits identicalto the circuit 113 disclosed in relation with FIG. 2. The circuit 425receives the binary word Code4 coming from the circuit 427 as input, andsupplies the datum Data4 as output. The circuit 426 receives the binaryword Code4 coming from the circuit 428 as input, and supplies the datumData4 as output. The circuits 405 and 425 can, for example, be part of asame circuit, but, as a variant, can be separate circuits. The circuits406 and 426 can, for example, be part of a same circuit, but, as avariant, can be separate circuits.

The binary word concatenation circuits 427 and 428 are circuitsidentical to the circuit 114 disclosed in relation with FIG. 2. Thecircuit 427 receives the binary words Code4A and Code4B as input, andsupplies the binary word Code4 as output. The circuit 428 receives thebinary words Code4A and Code4B as input, and supplies the binary wordCode4 as output. The circuits 407 and 427 can, for example, be part of asame circuit, but, as a variant, can be separate circuits. The circuits408 and 428 can, for example, be part of a same circuit, but, as avariant, can be separate circuits.

The circuits 412 and 413 convert the address AddL4 respectively into thephysical addresses Add4A and Add4B. The circuit 412 receives the logicaladdress AddL4 as input, and supplies the physical address Add4A asoutput. The circuit 413 receives the logical address AddL4 as input, andsupplies the physical address Add4B as output.

The memory circuits 409 and 410 store the binary words Code4A and Code4Brespectively at the addresses Add4A and Add4B. The memory circuit 409receives the address Add4A from the circuit 412, and the memory circuit410 receives the address Add4B from the circuit 413.

As a variant, the parts 40 and 42 could comprise more than two memorycircuits. In this case, the part 42 comprises as many circuits forchecking an error correcting or detecting code, as many circuits forrecovering a datum, and as many binary word concatenation circuits asthere are memory circuits in the part 41. Additionally, the binary worddividing circuits are configured to divide the binary word that theyreceive as input into a number of binary words equivalent to the numberof memory circuits comprised in the part 41. Additionally, the circuits412 and 413 are configured to supply as many physical addresses comingfrom the logical address AddL4 as there are memory circuits comprised inthe part 42.

The comparison circuit 431 is a circuit configured to compare, interalia, the addresses AddL4 transmitted by the processors 421 and 422, andthe data Data4 transmitted by the circuits 425 and 426. The comparisoncircuit 431 receives the address AddL4 supplied by the processor 421 andthe address AddL4 supplied by the processor 422 as input, and the datumData4 transmitted by the circuit 425 and the datum Data4 transmitted bythe circuit 426 as output. The comparison circuit 431 supplies an errorsignal ErrComp42 as output. If the addresses transmitted by theprocessors 421 and 422 are not identical, than an error is detected, andis transmitted by the error signal ErrComp42. The circuit 431 and thecircuit 411 described in relation with FIG. 7 can, for example, be partof a same circuit, but, as a variant, the circuits 411 and 431 can beseparate circuits.

A method for reading the datum Data4 implementing the part 42 of thesystem 4 in memory is as follows. The processors 421 and 422 supply thecircuits 412 and 413 with the address AddL4 at which they wish to read adatum, in the case at hand the datum Data4. The circuits 412 and 413supply the physical addresses Add4A and Add4B to the memory circuits 409and 410. The comparison circuit 431 checks whether the processors 421and 422 are transmitting the same address AddL4. The binary word Code4Ais stored at the address Add4A of the memory circuit 409, and the binaryword Code4B is stored at the address Add4B of the memory circuit 410.The memory circuits 409 and 410 supply the circuits 427 and 428 with thetwo binary words Code4A and Code4B to reform the binary word Code4. Thecircuit 425 occupies itself finding the datum Data4 from the binary wordCode4 transmitted by the circuit 427, the circuit 426 occupies itselffinding the datum Data4 from the binary word Code4 transmitted by thecircuit 428. The processor 421 then receives the datum Data4 from thecircuit 425, and the processor 422 receives the datum Data4 from thecircuit 426. The comparison circuit 431 checks the correspondencebetween the data Data4 supplied to the processors 421 and 422. Thecircuits 423 and 424 check, each on its side, the code EDC4.

One advantage of this embodiment is that, during the reading method, thecircuits 423 and 424 make it possible to detect an addressing error ofthe datum Data4. Indeed, the code EDC4 being representative of the datumData4 and the logical address at which the datum was written, thecomparison of the code EDC4 to a code generated from the logical addressAddL4 supplied by the processor 421 and 422 makes it possible to detecta difference in addresses.

Another advantage of this embodiment is that using two processors 401and 402, and 421 and 422, in parallel makes it possible to detect theerrors emitted during the reading control or the writing control. Theseerrors are detected by the circuits 411 and 431.

FIG. 9 shows, schematically and in block diagram form, part of a memorycircuit MEM. The memory circuit MEM is, for example, the memory circuittype used by the systems 1 to 4 disclosed in relation with FIGS. 1 to 8.

The part of the memory circuit MEM comprises a control circuit LOGIC anda line control circuit WL.

The control circuit LOGIC is a circuit configured to process the variouscontrols received from the system to which the memory circuit MEMbelongs. The circuit LOGIC receives, as input, an address Add and adatum Data to be written. The circuit LOGIC supplies the followingsignals as output: a signal CS for selecting the memory circuit MEM; asignal WEN for activating writing; a selection/column number signal COL;and a selection/row number signal LIN.

The address Add is preferably a physical address, that is to say, ableto be interpreted directly into row and column coordinates in the memorycircuit. In a variant, this address is a logical address supplied by theprocessor and translated by an address decoding circuit associated withthe memory circuit, that is to say, belonging to the memory circuit.

The signal CS makes it possible to select the memory circuit MEM duringa reading or writing operation.

The signal WEN makes it possible to indicate the nature of the receivedcontrol to the memory circuit MEM, and more specifically, whether awriting operation is requested.

The signals COL and LIN are the signals generated from the address Addreceived by the circuit LOGIC, and are the signals making it possible toselect the memory points (not shown in FIG. 9) of the memory circuit inwhich one wishes to write the datum Data.

The row control circuit WL is a circuit configured to select thewordline corresponding to the address Add received by the memorycircuit. The circuit WL receives the row selection/number signal LIN asinput, and supplies words WLN as output. In FIG. 9, only one word WLN isshown.

FIG. 10 shows, schematically and in block diagram form, part 50 of anarchitecture of an electronic system 5. The part 50 is configured todetect errors when writing data in memories.

The part 50 of the system 5 comprises: two memory circuits 51 (MEM3) and52 (MEM4); and a comparison circuit 53 (COMP).

The memory circuits 51 and 52 are memory circuits with an identicalstructure and size to the type of the memory MEM disclosed in relationwith FIG. 9. Thus, the memory circuits 51 and 52 each receive a physicaladdress Add5 as input. The memory circuit 51 further receives a binaryword Code5A to be stored at the address Add5 as input. The memorycircuit 52 further receives a binary word Code5B to be stored at theaddress Add5 as input. As disclosed in relation with FIG. 9, each memorycircuit 51, respectively 52, supplies the following output signals asoutput: a word WLN51, respectively WLN52; a signal CS51, respectivelyCS52, for selecting the memory circuit 51, respectively the memorycircuit 52; a signal WEN51, respectively WEN52, for activating writing;a selection/column number signal COL51, respectively COL52; and aselection/row number signal LIN51, respectively LIN52.

The binary words Code5A and Code5B are binary words of equal size bothrepresentative of a datum to be written in memory. As an example, thebinary words Code5A and Code5B are obtained by dividing the datum to bewritten in memory in half. According to another example, the binarywords Code5A and Code5B are obtained in the same way as the binary wordsCode1A and Code1B described in relation with FIG. 1.

The comparison circuit 53 is a circuit making it possible to compare theoutput signals of the two memory circuits 51 and 52 in order to detectan error during a writing operation. The comparison circuit 53 receivesthe following signals as input: the words WLN51 and WLN52; the signalsCS51 and CS52; the signals WEN51 and WEN52; the signals COL51 and COL52;and the signals LIN51 and LIN52.

The comparison circuit 53 supplies a comparison signal CompErr5 asoutput. The comparison circuit 53 more particularly compares each outputsignal of the memory circuit 51 with the counterpart output signal ofthe memory 52. In other words, the comparison circuit 53 is configuredto: compare the words WLN51 and WLN52; compare the signals CS51 andCS52; compare the signals WEN51 and WEN52; compare the signals COL51 andCOL52; and compare the signals LIN51 and LIN52.

The comparison circuit 53 can be an assembly of logic gates of theEXCLUSIVE OR type.

As a variant, the part 50 could comprise more than two memory circuits.In this case, the comparison circuit 53 is configured to receive all ofthe output signals of the memory circuits of the part 50 as input.Additionally, each of these memory circuits is configured to store abinary word representative of the datum to be written in memorydifferent from the binary words stored in the other memory circuits.

A method for detecting reading errors implementing the part 50 of thesystem 5 is as follows. During the writing of the binary words Code5Aand Code5B in the memory circuits 51 and 52 at the address Add5, thememory circuits 51 and 52 send their output signals to the comparisoncircuit 53. The binary words Code5A and Code5B being binary words ofequal size, stored at an identical address in identical memory circuits,thus, the output signals of the memory circuits 51 and 52 shouldtherefore be identical. The comparison circuit 53 then compares theoutput signals of the memory circuits 51 and 52, each difference betweentwo signals being able to signify an error. A potential error istransmitted by means of the signal CompErr5.

One advantage of this embodiment is that it makes it possible to detectthe address errors during a writing operation of a datum in memorywithout requiring a reading operation of said datum.

Various embodiments and variants have been described. Those skilled inthe art will understand that certain features of these embodiments canbe combined and other variants will readily occur to those skilled inthe art.

In particular, the embodiments disclosed in relation with FIGS. 1 and 2,3 and 4, 5 and 6, and 7 and 8 are all compatible with the embodimentdisclosed in relation with FIGS. 9 and 10.

Additionally, the embodiments disclosed in relation with FIGS. 3 and 4,5 and 6, and 7 and 8 comprise two identical processors, but as avariant, these embodiments could comprise more than two processors.

Finally, the practical implementation of the embodiments and variantsdescribed herein is within the capabilities of those skilled in the artbased on the functional description provided hereinabove.

1. A method for detecting a writing error of a datum in memory,comprising: storing at least two parts of equal size of a binary wordrepresentative of said datum at a same address in both a first memorycircuit and a second memory circuit, wherein the first and second memorycircuits are identical; generating, in response to said storing,internal control signal by each of the first and second memory circuits;and comparing the internal control signals generated by the first andsecond memory circuits and indicating said writing error when theinternal control signals do not match.
 2. The method according to claim1, wherein the internal control signals comprise a word signal.
 3. Themethod according to claim 1, wherein the internal control signalscomprise a selection signal.
 4. The method according to claim 1, whereinthe internal control signals comprise a writing activation signal. 5.The method according to claim 1, wherein the internal control signalscomprise a selection/column number signal.
 6. The method according toclaim 1, wherein the internal control signals comprise a selection/rownumber signal.
 7. The method according to claim 1, further comprisinggenerating said binary word from said datum and an error correcting ordetecting code.
 8. The method according to claim 7, further comprisinggenerating said error correcting or detecting code from said datum andsaid address.
 9. The method according to claim 7, wherein generatingsaid binary word comprises concatenating said datum and the errorcorrecting or detecting code.
 10. The method according to claim 7,wherein generating said error correcting or detecting code comprisesapplying a signature method.
 11. A memory system, comprising: a firstmemory circuit; a second memory circuit; wherein the first and secondmemory circuits are identical; a processing circuit configured to:generate a binary word representative of a datum; split the binary wordinto a first part and a second part, wherein the first and second partsare of equal size; write the first part for storage in the first memoryat a first address; write the second part for storage in the secondmemory at a second address, wherein the first and second addresses arethe same address; and a comparison circuit configured to compareinternal control signals generated by the first and second memorycircuits in response to the writing of the first and second parts,wherein a difference between the internal control signals is indicativeof a writing error.
 12. The memory system according to claim 11, whereinthe internal control signals comprise a word signal.
 13. The memorysystem according to claim 11, wherein the internal control signalscomprise a selection signal.
 14. The memory system according to claim11, wherein the internal control signals comprise a writing activationsignal.
 15. The memory system according to claim 11, wherein theinternal control signals comprise a selection/column number signal. 16.The memory system according to claim 11, wherein the internal controlsignals comprise a selection/row number signal.
 17. The memory systemaccording to claim 11, wherein generation of said binary word by saidprocessing circuit comprises generating said binary word from acombination of said datum with an error correcting or detecting code.18. The memory system according to claim 17, wherein said errorcorrecting or detecting code is generated from said datum and an addressused to generate said first and second addresses.
 19. The memory systemaccording to claim 17, wherein generation of said binary word by saidprocessing circuit comprises concatenating said datum and the errorcorrecting or detecting code.
 20. The memory system according to claim17, wherein generation of said binary word by said processing circuitcomprises applying a signature method.